Muffle plate



July 6, 1937. R. KIRKPATRICK 2,086,504

MUFFLE PLATE Filed March 5, 1956 Fig HUBERT K/RKPHTR/UK Patented July 6, 1937 PATENT OFFICE MUFFLE PLATE Robert Kirkpatrick, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application March 5, 1936, Serial No. 67,338

1 Claim.

The invention relates to muffle furnaces and to muille plates therefor, and with regard to its more specific features to plates for that type of furnace known as the Manion furnace.

One object of the invention is to provide an improved mume plate which will transmit an increased amount of heat. Another object of the invention is to provide a construction for a bottom plate for a furnace ofthe type indicated of w high heat conducting qualities yet adequate strength. Another'object of the invention is to provide a construction of the type indicated in which the ratio of conductance to strength is high. Another object of the invention is to improve the furnace described in United States Letters Patent to Leo W. Manion No. 1,607,681. Another object of the invention is to provide a construction for a furnace of the type indicated attaining a high temperature in the working chamber for a given temperature in the combustion chamber. Another object of the invention is to transmit heat so that the ware chamber shall have an even distribution thereof avoiding the localization or concentration thereof in a particular spot. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of' construction, combinations of elements, and arrangements of parts, all as will be illustratively described herein and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing showing one of many possible embodiments of the invention.

Fig. 1 is a vertical cross sectional view through a Manion type furnace equipped with muifle g plates according to the invention;

Fig. 2 is a plan view of a plate or tile;

Fig. 3 is a cross sectional view on the line 3--3 of Fig. 2;

' Fig. 4 is a cross sectional view on the line 4 4 of Fig. 2;

Figs. 5 and 6 are end elevations of the plate or tile of Fig. 2;

Fig. 7 is an enlarged cross sectional View showing the manner in which adjacent plates or tiles are joined together at the apexes of the bottom structure.

The Manion type of furnace is described in United States Letters Patent No. 1,607,681 aforesaid. While so far as certain features of the invention are concerned the plate or tile which is more specifically the subject matter of my invention is adapted for incorporation into such a furnace, it must be understood that it may also be used in other furnaces. In Fig. 1 I have shown so much of the Manion furnace as contributes to an undertstanding of the present invention. Referring to Fig. l, there is provided a bottom wall I0 and side walls II, I I. There are also provided spaced piles or piers I2 projecting from each side wall and in parallel relation, individual piles or piers on either side being opposite each other. Between the piles or piers I2 are additional piles or piers I3, I3 also in parallel evenly spaced rela- 10 tion, with individual piles or piers opposite each other and also opposite corresponding piles or piers I2. The piles or piers I2 and I3 taken all together define bottom combustion chambers I4 and which communicate with upwardly extend- 15 ing side combustion chambers I5. The furnace provides a ware chamber I6 which is separated from the side combustion chambers I5 by means of refractory side walls I1, I'I spaced from the main side walls II and comprising interlocked 2o refractory plates or tiles I8 the bottom rows of which rest upon the piers I2. The ware chamber I6 is separated from the combustion chambers I4 by means of a refractory V bottom construction which as a whole and the individual tile members of which more particularly constitute the subject matter of the present invention.

Referring now to Fig. 2, I provide a plurality of identical tiles or plates 20 together with a plurality of similar but oppositely oriented tiles or plates 20a all of which will be understood from the following description of the plate 20. The plate 20 may be made of any suitable refractory material, but I prefer to construct it of highly refractory granular material bonded together with 35 a refractory vitrified bond. Specifically I may use refractory grain of the material aluminum oxide or of the material silicon carbide or, for example, magnesium oxide or any other suitable refractory material. The bond may be a ceramic bond of .um high refractory qualities or any other suitable type, for example, self-bonded granular material may be employed and also the improved plates might be directly cast from a molten refractory.

Considering now the structure of the plates 45 20, and referring to all of Figs. 2, 3, 4, 5, and 6, each plate has a top surface having a plurality, for example three, grooves 2I therein. Each plate 20 has a bottom surface having a plurality, for example two, grooves 22 therein. 2| and 22 are all parallel to each other and evenly spaced so that the wall portion 23 between them is substantially of the same thickness between the opposite edges of the outermost grooves 22. From that point outward on each side, however,

The grooves 50 the material gradually increases in thickness to the ends 24 and 25; the end 24 being in this illustrative embodiment of the invention a grooved end, and the end 25 having a dovetail as shown.

One end 26 of each plate 20 is mitered forming dihedral angles with the top and bottom of the plate 20 of approximately 45 and forming a mitered edge of approximately 90. The other end of each plate 20 is divided into two equal parts; one of these comprises a dovetailed end 30, and the other comprises a groovecl end 3l having a groove 32 that is oriented in an angular position 90 from that of the dovetailed end 3D. This relationship Will be more readily apparent from a comparison of Figs. 2 and 6 and by reference also to Figs. 4 and 5.

The plates 20 are each of them joined With corresponding but oppositely oriented plates 20a to form the structure shown in Fig. 1, in which pairs of plates are joined together with each groove 32 of one plate resting on top of the dovetail or tongue of another plate. At one end of each pair of plates 20 and 20a are dovetails or tongues 25 while the other end of each pair of plates 20 and 20a are grooved ends 24. However, variations in the positions of tongues and grooves may be made, for example a particular end of a plate 20 might have a tongue while the end of the plate 20a in the same plane might have a groove, i. e. plates 20 can be interlocked.

In assembling the plates in the furnace, a pair of plates 20 and 20a may be interlocked together and pushed into position in -a line which is normal to the View in Fig. l.

With the plates arranged as described, there are three grooves 2l on the upper side of each plate and a pair of grooves 22 on the lower side of each plate. Nevertheless because the plates are of full thickness all along e-ach of the four ends thereof, each plate is substantially as strong as it would be were it of the same outline but solid. On the other hand, however, because the cross section for heat transference is very much less, a great deal more heat is conducted through each plate than is conducted through a solid of the same outline. Furthermore, because oi the broken upper surface of each plate heat diffusion is better achieved. I desire to avoid a concentration of heat at any one particular spot and I have found that a corrugated upper surface avoids such concentration.

Considering now the resistance of my plates to a load thereon, by reason of the fact that there are two central ridges 35, 35 as well as the thick portions 36 and 31 on the upper side of each plate, they are substantially as strong as they would be if solid. That is to say, removal of material in the manner described has, from a practical standpoint,l reduced the strength of each plate to resist a load on top of the apexes 40 to a substantially immaterial extent. 'Ihe plates can be assembled in a furnace in a very short time and the ends 26 abut against each other and against the walls 8 and hold the individual plates together to form a V bottom to the Ware ch-amber and a Vtop to the combustion chambers I4. At the same time the joints may be made quite tight so that the gases of combustion Will not reach the air chamber. Such slight openings as remain after the plates are pushed together are readily closed with cement. But because of the interlocking arrangement there is little tendency cf the gases to burn through the cement.

It Will thus be seen that there has been provided by this invention a muille plate in which the various objects hereinbefore set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be under-v stood that all matter hereinbefore set forth, or

shown in the accompanying drawing, is to be interpreted as illustrative and not in a limiting sense.

I claim:

A pair of muiile plates for a V bottom mulilez furnace, each plate being substantially rectangular and having depressions in its opposite sides lin the form of parallel grooves staggered so as to make the plate corrugated in cross section with marginal portions of a thickness the same as' the greatest amplitude of the corrugations, and along one marginal Wall of each plate there being for part of the distance a tongue portion and for the remainder of the distance ya groove portion, said tongue portion and said groove portion extending from planes of the margin at to each other, whereby the plates may be interlocked together to add strength.

ROBERT KIRKPATRICK. 

